1. Field of the Invention
This invention relates to accessories for the game of billiards, and in particular to a billiard cue tip and to a billiard cue.
2. Description Relative to the Prior Art
Interest and participation in the game of billiards has grown rapidly in the U.S. over the past decades. It is estimated that there are more than 36 million participants in the game at present, and they range across the spectrum of home and local billiard parlor amateur players to professional championship contestants. Along with this growth in participation and improvement in skills, there has been an increased demand for improved billiard accessories by both amateur and professional players.
An area of perennial interest has been the improvement of cue tips and cues for executing off center billiard shots, such as right and left English, draw and follow shots. Having the ability to skillfully execute these shots when challenged by the infinite number of ball positions possible on the table during a game is the mark of the proficient player. Such shots, where the direction of the force applied to the ball by the stroke of the cue does not go through the center of the cue ball so that spin is imparted to the cue ball, is described and fully analyzed in U.S. Pat. No. 5,725,437.
A successful off center shot requires non-sliding contact between the cue tip and the cue ball during impact. That is, during tip/cue ball engagement high friction is required, and this necessitates a large coefficient of static friction between the tip and the ball. A successful stroke imparts both controlled spin and forward motion to the cue ball. Over a long period of time and much experimentation, the overwhelming material of choice for the cue tip, by players of all calibers, has been leather. A wide variety of leathers have been utilized in tip fabrication, including pig skin, cowhide, elk, buffalo and boar hides, as well as the hides of more exotic animals, and the reason for the choice of leather has been, an acceptable but not necessarily optimum, coefficient of static friction between the tip and cue ball. During play, rubbing fine chalk particles from a chalk block onto the cue tip further enhances the friction.
Another important parameter affecting control of off-center billiard shots is the hardness of the leather cue tip. Cue tip hardness, or density, is measured by means of a durometer, and tip hardness ranges from a value of 60 for a soft tip to above 80 for a hard tip. Cue tips in the hardness range of 76-80, are characterized as medium hard tips, and are generally regarded as an optimum choice for typical play. Tip hardness selection is a matter of personal preference of the billiard player, and consideration of opposing parameters is of primary importance in tip selection. A soft tip gives more flexibility in an off center shot, while preservation of contour is better effected by a harder tip.
Despite the ongoing popularity of the leather tip, there have been continuing disclosures in the prior art exploring non-leather tips that claim superior friction characteristics. As far back as 1867, U.S. Pat. No. 71,925 disclosed a composition comprising a mixture of rubber, ground leather, chalk, emery and crocus from which a high friction cue tip is fabricated. U.S. Pat. No. 3,381,960 discloses a tip of a mixture of polyurethane elastomer and leather flour, while U.S. Pat. No. 3,695,611 discloses one comprising neoprene and filler.
Unlike the above proposed non leather cue tips, the cue tip of the present invention substantially increases the friction between the cue tip and cue ball without surrendering the use of the currently popular leather cue tip.